The invention relates generally to the area of magnetizers. More specifically, the invention relates to the area of magnetizers for magnets that are disposed in-situ in a mechanical member, such as a rotor of an interior permanent magnet machine, or a slider of a linear electric machine.
The rotors of many electric machines include permanent magnets that produce magnetic field flux, which magnetic field flux interacts electromagnetically with a stator. The electromagnetic interaction results in a conversion of electromagnetic energy to mechanical energy within the electric machine.
Interior permanent magnet electric machines constitute a class of electric machines in which the permanent magnets are buried within the bulk of the rotor. In an as-formed state, the permanent magnets do not have any net magnetic moment. However, the design principles of the electric machine require that the permanent magnets disposed within the bulk of the rotor be in a magnetized state before the electric machine can be put in operation.
Two approaches to magnetize the permanent magnets are known within the art. In the first approach, the permanent magnets are magnetized before they are disposed within the bulk of the rotor. This approach presents several drawbacks from the point of view of an industrial assembly process for electric machines. For instance, it will be appreciated that fully magnetized permanent magnet pieces would be subject to electromagnetic interaction with all surrounding objects, which in turn adds to the complexity of their handling procedures. In the second approach, as-formed permanent magnets are disposed within a rotor and a magnetizer is used to magnetize the permanent magnets. This approach also presents several drawbacks from the point of view of an industrial assembly process for electric machines. For instance, the energy and fabrication costs for magnetizers capable of generating, at the location of the permanent magnets, a magnetic field flux sufficient to magnetize the permanent magnets, are prohibitive. Typical prior art in-situ magnetizers are only able to economically magnetize permanent magnets disposed within low pole count rotors.
A magnetizer that is capable of economically providing user definable magnetic flux field configurations at the locations where the permanent magnets are disposed within the rotor, and having a design that is readily adaptable for electric machines of different sizes and configurations, would therefore be highly desirable.